---
title: GLM-5.2
description: "Deploy GLM-5.2 with SGLang — Z.ai's DeepSeek-Sparse-Attention (DSA) Mixture-of-Experts model with MTP speculative decoding and 1M context, on H200, B200, B300, GB300, and AMD MI300X/MI325X/MI355X."
tag: NEW
---

## Deployment

<a id="install" />

<Accordion title="Install SGLang">

For all methods and hardware platforms, see the [official SGLang installation guide](../../../docs/get-started/install). The two paths below match the **Python / Docker** toggle in the command panel.

<Tabs>

<Tab title="Python (pip / uv)">

```bash Command
pip install --upgrade pip
pip install uv
uv pip install sglang
```

Then run the **Python** output of the command panel below in that environment.

</Tab>

<Tab title="Docker">

```bash Command
docker pull lmsysorg/sglang:latest
```

For how to launch the image, see [Install → Method 3: Using Docker](../../../docs/get-started/install#method-3-using-docker). Substitute the inner `sglang serve ...` with what the command generator below produces.

</Tab>

</Tabs>

</Accordion>

Pick your hardware + recipe to generate the launch command. The three serving strategies cover the common operating points:

- **Low-Latency** — fastest reply for a single user. Pick for chat.
- **Balanced** — good speed with several users at once. Use for typical multi-user serving.
- **High-Throughput** — most tokens per second across many users. Best for batch jobs.

import { Deployment } from "/src/snippets/_deployment.jsx";
import { config }     from "/src/snippets/configs/zai-org/glm-5.2.jsx";
import { benchmarks } from "/src/snippets/configs/zai-org/glm-5.2-benchmarks.jsx";

<Deployment config={config} benchmarks={benchmarks} />

<Warning>
  All recipes here run the DSA indexer top-k on the default `--dsa-topk-backend sgl-kernel`. Other top-k backend choices have not been fully validated on GLM-5.2.
</Warning>

<Note>
  Speed numbers are measured with `--random-range-ratio 1.0`, `--flush-cache`, on `main @ 09ca4fc`. Spec cells pin the EAGLE acceptance length via the serve env `SGLANG_SIMULATE_ACC_LEN` (low-latency 5-1-6 = 3.5, balanced 2-1-3 = 2); high-throughput has no spec.
</Note>

## Playground

The Playground is where you experiment with **SGLang features beyond the verified matrix**. The Deploy panel above only emits combinations the SGLang team has signed off on; the Playground lets you turn on additional knobs on top of whichever cell the Deploy panel is currently showing.

import { Playground } from "/src/snippets/_playground.jsx";

<Playground config={config} />

## 1. Model Introduction

**GLM-5.2** is Z.ai's flagship Mixture-of-Experts model built on **DeepSeek Sparse Attention (DSA)**: a lightning indexer selects a sparse set of key tokens per query (top-2048), so attention cost stays near-constant as context grows. It ships in two precisions — **FP8** (`zai-org/GLM-5.2-FP8`) and full **BF16** (`zai-org/GLM-5.2`) — both with **78 transformer layers**, **256 routed experts** (8 active per token), a **1M-token context window**, and a single **MTP (Multi-Token Prediction)** layer for built-in EAGLE-style speculative decoding. FP8 is the recommended deployment; BF16 (~1.5 TB) needs an 8×B300 node or a multi-node setup. For Blackwell, NVIDIA also publishes an **NVFP4** build (`nvidia/GLM-5.2-NVFP4`) that quantizes only the MoE experts' linear weights and activations to 4-bit (the shared expert stays unquantized), holding accuracy within ~1 point of the FP8 baseline on GPQA Diamond, SciCode, and IFBench.

<table style={{width: "100%", borderCollapse: "collapse", tableLayout: "fixed"}}>
  <thead>
    <tr style={{borderBottom: "2px solid #d55816"}}>
      <th style={{textAlign: "left",  padding: "10px 12px", fontWeight: 700}}>Model</th>
      <th style={{textAlign: "left",  padding: "10px 12px", fontWeight: 700}}>Architecture</th>
      <th style={{textAlign: "left",  padding: "10px 12px", fontWeight: 700}}>Context</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td style={{padding: "9px 12px"}}><strong><a href="https://huggingface.co/zai-org/GLM-5.2-FP8">GLM-5.2-FP8</a></strong></td>
      <td style={{padding: "9px 12px"}}>MoE · DSA · 256 experts (top-8) · MTP · FP8</td>
      <td style={{padding: "9px 12px", textAlign: "right"}}>1,048,576</td>
    </tr>
    <tr>
      <td style={{padding: "9px 12px"}}><strong><a href="https://huggingface.co/zai-org/GLM-5.2">GLM-5.2</a></strong></td>
      <td style={{padding: "9px 12px"}}>MoE · DSA · 256 experts (top-8) · MTP · BF16</td>
      <td style={{padding: "9px 12px", textAlign: "right"}}>1,048,576</td>
    </tr>
    <tr>
      <td style={{padding: "9px 12px"}}><strong><a href="https://huggingface.co/nvidia/GLM-5.2-NVFP4">GLM-5.2-NVFP4</a></strong></td>
      <td style={{padding: "9px 12px"}}>MoE · DSA · 256 experts (top-8) · MTP · NVFP4</td>
      <td style={{padding: "9px 12px", textAlign: "right"}}>1,048,576</td>
    </tr>
  </tbody>
</table>

**Recommended generation:** `temperature=1.0`, `top_p=0.95` (the checkpoint's `generation_config.json` defaults; informational — do not hardcode in client code).

**Resources:** [GLM-5.2-FP8](https://huggingface.co/zai-org/GLM-5.2-FP8) · [GLM-5.2 (BF16)](https://huggingface.co/zai-org/GLM-5.2) · [GLM-5.2-NVFP4](https://huggingface.co/nvidia/GLM-5.2-NVFP4).

## 2. Configuration Tips

- **DeepSeek Sparse Attention (DSA).** GLM-5.2 uses the `glm_moe_dsa` architecture; SGLang auto-selects the DSA attention backends (`flashmla_sparse` prefill, `fa3` decode, `sgl-kernel` indexer topk). No attention-backend flag is needed on the supported hardware. SGLang also auto-selects the KV-cache dtype for DSA models — `fp8_e4m3` on Blackwell (B200/GB300/B300, which then routes DSA through the TensorRT-LLM backend) and `bf16` on Hopper (H200) — so no `--kv-cache-dtype` flag is required. On Hopper, pairing `--kv-cache-dtype fp8_e4m3` with `--dsa-prefill-backend flashmla_sparse_q8 --dsa-decode-backend flashmla_kv` selects the native FP8 sparse prefill kernel (computes directly on the fp8 KV cache with no fp8→bf16 dequantization round-trip; GLM-5.2's 64 query heads match the kernel's native tile) — see the [DeepSeek-V3.2 page](../DeepSeek/DeepSeek-V3_2) for kernel details; the optional `SGLANG_ENABLE_DSA_Q8KV8_*` performance env vars are documented in `python/sglang/srt/environ.py`.
- **MTP / speculative decoding.** The checkpoint ships one nextn layer. Enable EAGLE MTP for lower latency (`--speculative-algorithm EAGLE --speculative-num-steps 5 --speculative-eagle-topk 1 --speculative-num-draft-tokens 6` for low-latency; `1-1-2` for balanced). The config's `index_share_for_mtp_iteration` reuses the DSA indexer's topk across draft steps (effective only at `--speculative-eagle-topk 1`). **Tune the draft length to the accept length.** GLM-5.2's MTP head is strong — accept length runs high (4+ in many workloads, near-saturating at 5–6 in low-latency runs). Watch the server's reported **accept length** and adjust `--speculative-num-steps` / `--speculative-num-draft-tokens` accordingly: while accept length stays close to the draft-token count there is headroom to push them higher (more accepted tokens per step); if it falls well below, lower them — every rejected draft token is wasted verification compute.
- **Memory.** The FP8 weights are large (MoE total, not active params). Start around `--mem-fraction-static 0.8` on H200 (TP8) and tune up; raise it for the 4-GPU GB300 single-node layout (TP4).
- **DP-Attention + DeepEP** for the balanced/high-throughput strategies spreads attention across data-parallel ranks and routes MoE through DeepEP.
- **BF16 weights need more GPUs.** The full-precision build (`zai-org/GLM-5.2`, ~1.5 TB) does not fit a single 8×H200 / 8×B200 / 4×GB300 node. It fits single-node on **8×B300** (TP8, ~2.1 TB HBM) — **verified**; on the smaller GPUs it needs a **multi-node** layout (e.g. 2×8×H200 or 2×8×B200 at TP16, 2×4×GB300 at TP8), and those **multi-node BF16 recipes are still proposed/inferred** (`verified: false`). FP8 is the recommended deployment. Use the same DSA / MTP / chunked-prefill guidance as FP8. On B300, BF16 low-latency matches FP8 (the sm103 FP8 path is not yet optimized), but FP8 wins at the balanced/high-throughput points.
- **PD Disaggregation (prefill/decode).** GLM-5.2 is a DSA model and runs under prefill/decode disaggregation — toggle the **PD Disagg** card in the [Playground above](#playground) (pick a Prefill/Decode role + transfer backend, then front the roles with `sglang_router.launch_router --pd-disaggregation`). The Mooncake backend **auto-detects the InfiniBand HCA**, so no device flag is needed by default; only add `--disaggregation-ib-device mlx5_0` (your NIC) if auto-detection picks the wrong device or KV transfer fails to connect. On H200 Docker, expose the IB HCAs to the container (`--privileged --ulimit memlock=-1`, or `--device /dev/infiniband:/dev/infiniband --cap-add IPC_LOCK`) — without IB exposure Mooncake silently falls back to TCP.
- **Chunked-prefill size is regime-dependent.** At long input (8K+) the default `--chunked-prefill-size 2048` is too small and leaves the balanced point prefill-bound (queueing dominates TTFT). Raising it to `--chunked-prefill-size 32768` on the balanced recipe gave roughly **+34–78% output throughput and −39–59% TTFT** on 8×H200 and 8×B200 (8K-in / 1K-out) in our testing. It is **neutral for high-throughput** (decode-bound there) — keep the default. `--max-running-requests` tracks KV capacity, not a tuning free-for-all: ~60–90 concurrent 8K+1K FP8 requests fit on a single 8-GPU node, so pin balanced near `--max-running-requests 80` and let high-throughput run wider.

- **AMD GPUs (MI300X / MI325X / MI355X).** FP8 (`zai-org/GLM-5.2-FP8`) runs single-node at `tp=8` on all three. BF16 (`zai-org/GLM-5.2`, ~1.51 TB) only fits single-node on **MI325X** (2 TB HBM) and **MI355X** (2.3 TB); **MI300X** (1.5 TB) cannot hold the BF16 weights plus KV cache on one node, so use FP8 there (or a multi-node BF16 layout once validated). Use the DSA tilelang backend (`--dsa-prefill-backend tilelang --dsa-decode-backend tilelang`) and add `--chunked-prefill-size 131072` plus `--watchdog-timeout 1200` (20 min for weight loading). FP8 uses about half the memory of BF16 (~89 GB/GPU vs ~175 GB/GPU). GLM-5.2 and DeepSeek-V3.2 share the same model structure; for other DSA / HiSparse tips see the [DeepSeek-V3.2 cookbook](../DeepSeek/DeepSeek-V3_2).

<Note>
**gfx950 block-FP8 accuracy: fixed as of the pinned MI355X image (`v0.5.13.post1-rocm720-mi35x-20260618`).** Earlier SGLang ROCm images miscompiled AMD aiter's `gemm_a8w8_blockscale_bpreshuffle` GEMM on gfx950 (ROCm 7.2): the error was small per layer but compounded across all 78 layers and silently corrupted output — in-context reasoning broke (GSM8K ≈ 0) while short factual prompts still looked fine. The root cause was a gfx950/ROCm-7.2 miscompile of the CK kernel (a packed illegal-type FMA that relied on an LLVM coercion pass removed in ROCm 7.2; non-deterministic wrong rows near tile boundaries). This is resolved in the pinned image and newer: GLM-5.2-FP8 on MI350X/MI355X (gfx950) was re-validated at TP4 and TP8 — **GSM8K ≈ 0.96 (0% invalid)** and **15/15 needle-in-haystack retrieval to ~118K tokens**. **MI300X / MI325X (gfx942) were never affected.** If you must run an older image, treat gfx950 FP8 output as unverified. Background: [sgl-project/sglang#28685](https://github.com/sgl-project/sglang/issues/28685) (analysis) and the upstream CK fix [ROCm/rocm-libraries#8639](https://github.com/ROCm/rocm-libraries/pull/8639) (scalar FMA + accumulator anchor; restores correctness and determinism at -O3).
</Note>

- **MTP / EAGLE speculative decoding** is disabled for AMD in the Deploy panel. The block-FP8 accuracy bug that previously degraded it is now fixed (see note above), but MTP on gfx950 still depends on the spec-decode draft kernel, which is not yet validated on this hardware (and at `--speculative-num-steps > 3` hits a separate build issue). Until MTP is validated on gfx950, omit the `--speculative-*` flags and serve without MTP.

## 3. Advanced Usage

### 3.1 Reasoning

GLM-5.2 is a hybrid-reasoning model. Enable the `glm45` reasoning parser (toggle **Reasoning Parser** in the **Parsers** card of the [Playground above](#playground)) to separate thinking from the final answer — thinking lands in `message.reasoning_content`, the answer in `message.content`. Thinking is on by default; turn it off with `chat_template_kwargs: {"enable_thinking": False}` (the template variable is `enable_thinking`, not `thinking`).

**Reasoning effort.** Pass `chat_template_kwargs: {"reasoning_effort": ...}` to inject a `Reasoning Effort: <level>` system line (only while thinking is on). **The template wires only two effective levels — `Max` and `High` — and if you don't pass `reasoning_effort` at all you get `Max`, the highest.** `"high"` is the *only* value that lowers effort; every other value (including `"low"` and `"medium"`) falls through to `Max`:

| `reasoning_effort` | Injected system line | Effect |
|---|---|---|
| *(not passed / unset)* | `Reasoning Effort: Max` | **default — highest reasoning** |
| `"high"` | `Reasoning Effort: High` | dials reasoning **down** |
| `"low"`, `"medium"`, any other value | `Reasoning Effort: Max` | falls through to `Max` (not a distinct level) |

<Accordion title="Reasoning Example (Python)">

```python Example
from openai import OpenAI

client = OpenAI(base_url="http://localhost:30000/v1", api_key="EMPTY")
resp = client.chat.completions.create(
    model="zai-org/GLM-5.2-FP8",
    messages=[{"role": "user", "content": "What is 15% of 240?"}],
    extra_body={"chat_template_kwargs": {"enable_thinking": True, "reasoning_effort": "high"}},
)
msg = resp.choices[0].message
print("Reasoning:", getattr(msg, "reasoning_content", None))
print("Answer:", msg.content)
```

</Accordion>

<Accordion title="Example Output">

```text Output
Reasoning: 1.  **Identify the core question:** The user wants to find 15% of 240.
2.  **Convert the percentage to a decimal:** 15% = 0.15
3.  **Multiply by the total:** 0.15 * 240 = 36
    (Quick mental math: 10% of 240 = 24; 5% = 12; 24 + 12 = 36.)

Answer: 15% of 240 is **36**.

Here is how you can calculate it:
0.15 × 240 = 36
```

</Accordion>

### 3.2 Tool Calling

Enable the `glm47` tool-call parser (toggle **Tool Call Parser** in the **Parsers** card of the [Playground above](#playground)) to surface structured tool calls via `message.tool_calls`. GLM-5.2 emits the newer `<tool_call>…<arg_key>…<arg_value>…` format, so it needs the **`glm47`** parser — the older `glm45` parser does not parse it (the call would be left as raw text in `content`). On thinking mode the turn also fills `reasoning_content`, so print both fields.

<Accordion title="Tool Calling Example (Python)">

```python Example
from openai import OpenAI

client = OpenAI(base_url="http://localhost:30000/v1", api_key="EMPTY")
tools = [{
    "type": "function",
    "function": {
        "name": "get_weather",
        "description": "Get the current weather for a city",
        "parameters": {
            "type": "object",
            "properties": {"city": {"type": "string"}},
            "required": ["city"],
        },
    },
}]
resp = client.chat.completions.create(
    model="zai-org/GLM-5.2-FP8",
    messages=[{"role": "user", "content": "What's the weather in Paris?"}],
    tools=tools,
)
msg = resp.choices[0].message
print("Reasoning:", getattr(msg, "reasoning_content", None))
print("Tool calls:", msg.tool_calls)
```

</Accordion>

<Accordion title="Example Output">

```text Output
Reasoning: The user wants to know the weather in Paris. I'll call the get_weather function with "Paris" as the city.

Tool calls: [
  {
    "id": "call_13fcd52146934b7781d06d4a",
    "type": "function",
    "function": {"name": "get_weather", "arguments": "{\"city\": \"Paris\"}"}
  }
]
```

</Accordion>

### 3.3 HiCache (Hierarchical KV Caching)

For long-context, prefix-heavy workloads, enable hierarchical KV caching to spill cold KV blocks to host memory (toggle the **Hierarchical KV Cache** card in the [Playground above](#playground)). Useful given GLM-5.2's 1M-token window; pair `--hicache-ratio` with a write policy that matches your reuse pattern.

### 3.4 Claude Code Integration

GLM-5.2's strong reasoning + tool-calling makes it a good backend for [Claude Code](https://code.claude.com/docs/en/overview), Anthropic's agentic CLI. SGLang exposes the Anthropic-compatible `/v1/messages` endpoint on every server, so Claude Code can talk to a GLM-5.2 server with only environment variables — no code change. Launch the server with `--reasoning-parser glm45 --tool-call-parser glm47` (any recipe from the Deployment panel above works), then:

```bash Command
export ANTHROPIC_BASE_URL="http://127.0.0.1:30000"
export ANTHROPIC_AUTH_TOKEN="dummy"
export API_TIMEOUT_MS="3000000"
export CLAUDE_CODE_AUTO_COMPACT_WINDOW="1000000"
export CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC=1
export CLAUDE_CODE_ATTRIBUTION_HEADER=0
export ANTHROPIC_DEFAULT_HAIKU_MODEL="glm-5.2[1m]"
export ANTHROPIC_DEFAULT_SONNET_MODEL="glm-5.2[1m]"
export ANTHROPIC_DEFAULT_OPUS_MODEL="glm-5.2[1m]"
claude
```

Two of these matter specifically for GLM-5.2:

- **`CLAUDE_CODE_ATTRIBUTION_HEADER=0`** — Claude Code prepends a per-request attribution block to the system prompt. GLM-5.2's chat template renders `tools` **before** `system`, so that per-request hash is the first token to diverge between turns and the radix prefix cache re-prefills the whole system + history every turn. This env removes the block and restores prefix-cache reuse.
- **`glm-5.2[1m]`** as the model name — the `[1m]` suffix is the client-side hint that enables Claude Code's 1M-context beta, matching GLM-5.2's 1,048,576-token window. Without it, context is capped well below 1M. SGLang does not validate the `model` field, so any name is accepted server-side.

For the full setup (streaming, tool-use, count_tokens, persisting env in `~/.claude/settings.json`, troubleshooting), see [Anthropic-Compatible API](../../../docs/basic_usage/anthropic_api).

### 3.5 Context Parallelism

Prefill context parallelism can help with reduction of TTFT under long context. To enable prefill context parallelism for GLM 5.2, please append the following arguments:
```bash
--attn-cp-size 8 \
--enable-prefill-cp \
--cp-strategy interleave \
```
which splits the sequence equally across `--attn-cp-size` ranks during attention forward. The trade off for prefill CP is that it will introduce extra all-gather operation before indexer-topk and attention kernels, so it will increase latency for decode (in unified deployment) or short prefill.

When deploying with PD Disaggregation, the prefill node can choose to enable [LayerSplit](https://z.ai/blog/scaling-pain) technique with
```bash
--enable-dsa-cache-layer-split \
--attn-cp-size 8 \
--cp-strategy interleave \
```
With LayerSplit, the kv cache on each rank can be sharded over the CP attention group, and prefetched when necessary. This can reduce kv cache memory by up to 75%, thus increasing the throughput on prefill side.
